The use of tropical root starches in bread making

Abstract

The physico-chemical properties of tropical root starches from arrowroot, cassava, sweet potato, taro, and yam were studied in order to clarify their possible incorporation and role in a bread making formulation. These properties were then compared with those of starches from a Canadian western red spring wheat (CWRSW) (cv. Neepawa) of good baking, and a soft white spring wheat (SWSW) (cv. Fielder) of inferior baking quality. A flour composite formula of 85% starch and 15% vital gluten was adopted for all starches. Bread from pure wheat flours obtained from Neepawa and Fielder were used as the standard and internal references. Based on the influences in bread making of starch granule size distribution and morphology, percent amylose and mineral contents, water binding capacities, swelling power and solubilities, gelatinization properties and enthalpies of~fusion, gel viscosity, retrogradation in gels, affinity for gluten, interaction with monoglycerides, dough rheological properties, bread qualities in the presence and absence of monoglyceride, and sensory evaluation, it was concluded that wheat starches made better composite breads than root starches with the same grade of vital gluten. Of the root starches, cassava produced the best composite bread next in quality to those of the wheat starches, followed respectively by yam, sweet potato, taro and lastly by arrowroot starch. Subtle differences between starch composite breads and the standard wheat flour breadindicated the need for the establishment of proper formulations and baking conditions for the compositebreads. The study, however, demonstrated that root starches possess varying potentials of being used in composite bread making with gluten or strong wheat flours. The study, in addition, has provided fundamental results which could be useful in further baking investigations involving root tuber flours, since such flours are predominantly composed of starch